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Can slow motion replays really make things look worse than they are?

The recent furore over the Sam Cane v Robbie Henshaw collision in the second test between Ireland and New Zealand got me to thinking about the merits of using slow motion video to make judgements about potential foul play incidents in rugby. I think we have all heard the meme that sometimes, looking at something at full speed gives a better sense of what really happened than watching it in slow motion, and that sometimes, a slow motion replay can actually make an incident look a lot worse than it really was (that is certainly my view on the incident I mentioned above).

So, I decided to go looking to see what an internet search would bring up on the issue, and not only was I surprised find that it is a real and known effect, but there is also a sound scientific basis for why this happens; it is due to something called "Slow Motion Intentionality Bias". It means that while you are watching a piece of video of an incident in slow motion, your brain is still operating in real time, so your perception of the available reaction time becomes distorted, your perception is that there was more time than there really was. This is not BS, its real, and is becoming something of a worry for criminal defence and prosecution lawyers with the increasing amount of video evidence being shown in courts and legal proceedings.

Here are the Significance Statement and the Abstract from a scientific study, published March this year, in the Proceedings of the National Academy of Sciences of the United States of America.

SIGNIFICANCE
When determining responsibility for harmful actions, people often consider whether the actor behaved intentionally. The spread of surveillance cameras, “on-officer” recording devices, and smart-phone video makes it increasingly likely that such judgments are aided by video replay. Yet, little is known about how different qualities of the video, such as replay speed, affect human judgment. We demonstrate that slow motion replay can systematically increase judgments of intent because it gives viewers the false impression that the actor had more time to premeditate before acting. In legal proceedings, these judgments of intent can mean the difference between life and death. Thus, any benefits of video replay should be weighed against its potentially biasing effects.

ABSTRACT
To determine the appropriate punishment for a harmful action, people must often make inferences about the transgressor’s intent. In courtrooms and popular media, such inferences increasingly rely on video evidence, which is often played in “slow motion.” Four experiments (n = 1,610) involving real surveillance footage from a murder or broadcast replays of violent contact in professional football demonstrate that viewing an action in slow motion, compared with regular speed, can cause viewers to perceive an action as more intentional. This slow motion intentionality bias occurred, in part, because slow motion video caused participants to feel like the actor had more time to act, even when they knew how much clock time had actually elapsed. Four additional experiments (n = 2,737) reveal that allowing viewers to see both regular speed and slow motion replay mitigates the bias, but does not eliminate it. We conclude that an empirical understanding of the effect of slow motion on mental state attribution should inform the life-or-death decisions that are currently based on tacit assumptions about the objectivity of human perception.

I know there are a few of you here with a scientific bent so you might find the whole thing interesting. You can read the full scientific study here (free, not behind a paywall).

Warning: there is some video in this link that some may find disturbing. Its probably work safe but not child safe - the link itself is safe because none of the video will start automatically.

Now, I do not pretend to understand 100% the detailed science in this paper. I had to gloss over quite a bit of the detail as much of it was over my head, but I understand enough to realise that it is a real effect.